This invention relates to a waterproof cover structure of an electric distribution box in which water, applied from the upper side, is prevented from intruding through a joined portion of two covers.
FIGS. 6 and 7 show a first related waterproof cover structure of an electric distribution box (See Pages 3 to 5, FIGS. 2 and 3 of JP-UM-55-129479).
This electric distribution box 41 includes main cover 42 made of a synthetic resin, and base cover 43. Electrical parts (such as relays) and a circuit board (not shown) for connecting the electrical parts, and so on are received within the two covers. A wire 45, extending from the circuit board, is extended outwardly through a mouth portion 44 formed at lower sides of the two covers 42 and 43.
The main cover 42 includes a frame-like peripheral wall 46 formed at a peripheral edge of an opening thereof through a stepped portion 48. The base cover 43 includes a frame-like wall portion 47 (FIG. 7) for fitting into the peripheral wall 46. As shown in FIG. 7, an upper wall portion 46a of the main cover 42 has a downwardly-slanting wall 49, and a lower end 49a of the slanting wall 49 is disposed in proximity to an outer surface of an upper wall portion 50 of base cover 43, thereby preventing the intrusion of water applied from the upper side.
The electric distribution box 41 is mounted within an engine room of a vehicle. When water is applied to an upper portion of the main cover 42, for example, during the travel of the vehicle, the water flows along the slanting wall 49 to the wall portion 50 of base cover 43. Even when the water intrudes into the inside of the wall portion 46a through a gap between the slanting wall 49 and the wall portion 50, the frame-like peripheral wall 47 of base cover 43 prevents the water from intruding to a surface (area) 51 of joining of the two covers 42 and 43.
In the above related structure, however, waterdrops remained on the inner surfaces of the slanting wall 49 and frame-like peripheral wall 47 for a long period of time, and the waterdrops are formed into vapor, and there is a fear that this moisture intruded through the joining area 51 into the inside of the covers, and adversely affected the electrical parts and the circuit board within the covers. There is also a fear that the upper wall portion 50 of the cover 43 is deteriorated by waterdrops, and is lowered in strength.
FIG. 8 shows a second related electric distribution box mounted within an instrument panel of a vehicle.
This electric distribution box 61 includes main cover 62, and base cover (ECU cover) 63. A wiring board 8, an ECU (electronic control unit) 7 and so on are received within the two covers 62 and 63.
A peripheral wall 64 of the ECU cover 63 is joined to an outer surface of a peripheral wall 65 of the main cover 62, and the two covers are fixed to each other by retaining member (not shown) including retaining projections and engagement holes. The electric distribution box 61 is mounted in a vertical posture within the instrument panel.
The scattering of a large amount of waterdrops as within the engine room will not occur within the instrument panel. However, in some cases, there occurs the intrusion of a small amount of water, such as dew condensation on an air duct and water intruding through a welded portion of a body, and in such a case there is a fear that the water intruded into the inside of the covers through a gap between the upper wall 65 of the main cover 62 and the upper cover 64 of the ECU cover 63 as indicated by arrow D.
And besides, when the retaining projections (not shown) are formed on the inner surface of each vertical side wall of the ECU cover 63 while the engagement holes (not shown) are formed in each vertical side wall of the main cover 62, there is a fear that water, passed through the gap between the upper walls 64 and 65 of the two covers 62 and 63, is liable to intrude into the inside of the covers through the engagement holes.
It is therefore an object of the present invention to provide a waterproof cover structure of an electric distribution box in which waterdrops, resulting from water applied from the upper side, can be rapidly removed, thereby positively preventing the intrusion of the water into the electric distribution box.
In order to achieve the above object, according to the present invention, there is provided a waterproof cover structure of an electric distribution box, comprising:
a first cover member, including:
a covering wall;
a first side wall, formed on the covering wall; and
an inner wall, formed on the covering wall with a gap between the first side wall and the inner wall, and having a straight wall and a slanting wall; and
a second cover member, having a second side wall to be inserted into the gap,
wherein the covering wall has an opening communicating the gap with an exterior; and
wherein an end portion of the second side wall is disposed above the slanting wall when the second side wall is inserted into the gap.
With this construction, when attaching the two covers to each other, the second side wall of the second cover member is inserted into the gap between the side wall of the first cover member and the inner wall, and the edge portion of the second side wall of the second cover member moves over the inner wall, and is disposed in overlying relation to the slanting wall. The slanting wall is disposed beneath the edge portion of the second side wall of the second cover member. Water, applied onto the second side wall of the second cover member, flows through the gap between the first side wall of the first cover member and the inner wall, and drops from the edge portion of the second side wall of the second cover member onto the surface of the slanting wall, and is smoothly led to the exterior along the slanting wall. Therefore, waterdrops, resulting from water applied from the upper side, can be rapidly removed, thereby positively preventing the intrusion of the water into the electric distribution box. Therefore, the quality of the circuit parts and so on within the electric distribution box is maintained, and besides the strength of the synthetic resin-molded covers will not be deteriorated, and the discoloring of the covers is prevented.
Preferably, the straight wall is continuous with the slanting wall. The slanting wall is continuous with the cover wall.
Preferably, the end portion of the second side wall is disposed outwardly of the straight wall in a direction of inserting of the second side wall of the second cover member.
With this constructions, when attaching the two covers to each other, the edge portion of the second side wall of the second cover member moves over the inner wall, and is disposed above the slanting wall in opposed relation thereto. The slanting wall is disposed beneath the edge portion of the second side wall of the second cover member in opposed relation thereto. The edge portion of the second side wall of the second cover member and the inner wall are disposed in horizontally-spaced relation to each other, and the inner wall is disposed close to the inner side of the electric distribution box, while the edge portion of the second side wall of the second cover member is disposed adjacent to the outer side of the electric distribution box. Water, applied onto the second side wall of the second cover member, positively drops from the edge portion of the second side wall of the second cover member onto the surface of the slanting wall without flowing back to the inner wall, and is more smoothly led to the exterior along the slanting wall. Therefore, the intrusion of water into the electric distribution box is more positively prevented.
Preferably, a notch is formed on a vicinity of the second side wall of the second cover member. The inner wall is inserted into the notch when the second side wall is inserted into the gap.
With this construction, when attaching the two covers to each other, the inner wall of the first cover member is inserted into the notch on the second cover member, and the first side wall of the first cover member is laid on the second side wall of the second cover member. When the inner wall is engaged in the notch, the inner wall and the second side wall of the second cover member are accurately positioned relative to each other, and the inner wall is held in intimate contact with the second side wall of the second cover member. Therefore, the intrusion of water through a gap between the inner wall and the second side wall of the second cover member is more positively prevented.
Preferably, a rib is formed on the first cover member so as to interconnect the slanting wall with the first side wall of the first cover member.
With this construction, the gap between the side wall of the first cover member and the inner wall will not be much increased, and the accurate dimensions are maintained by the rib, and the intimate contact of the inner wall with the second side wall of the second cover member is enhanced. Therefore, the waterproof performance is enhanced. And besides, the structure of the cover around the gap is reinforced by the rib, so that the mechanical strength increases, and for example the force of locking the two covers to each other increases, and this eliminates a disadvantage that the locking of the covers is accidentally canceled by vibrations or others, so that water intrudes into the inside of the covers.
Preferably, a retaining projection is formed on the second cover member. An engagement wall portion for engaging with the retaining projection is formed on the first cover member.
With this construction, simultaneously when attaching the two covers to each other, the retaining projection slide over the engagement wall, and is engaged with the engagement wall, thereby firmly locking the two covers to each other. The retaining projection and the engagement wall are used in combination as the retaining member, and through hole (engagement hole) is not used as the retaining member, and this eliminates a disadvantage that water intrudes into the inside of the covers through such engagement hole. Therefore, the waterproof performance of the electric distribution box is
Preferably, the first cover member is provided at each of opposite sides of the second cover member.
With this construction, the opposite sides of the second cover member are open, and circuit parts and so on can be efficiently mounted in the second cover member through the two openings. The two covers close the two openings in the second cover member. In each of the two covers provided respectively at the opposite sides of the second cover member, water is smoothly and positively led to the exterior by the inner wall and the slanting wall as described above. Particularly, water on the second side wall of the second cover member is efficiently and rapidly discharged by the slanting walls disposed respectively at the opposite sides, thereby positively preventing the water from intruding into the electric distribution box.